Merge pull request #150 from p-push/setup

Miscellaneous changes related to setup
Move unix to precede windows
Add ExtensionConfiguration class to hold the global variables in setup.py for future unit testing
Test coverage for pulling ssl library out of --libs and --static-libs of curl-config
Add tests for HAVE_CURL_SSL define
Achieve the same effect with a single variable
On travis we set PYCURL_SSL_LIBRARY, clear it in the setup test
Test that --static-libs libraries are ignored if --libs succeeds